Signaling system



4DSC. 24, 1940. L 'C RQBERTS 2,225,887

SIGNALING SYSTEM Filed Jan. 2'7, 1939 7 Sheets-Sheet 1 7 n n 4n 7L FFF 8 i g2* gm u. /0 l 1 H. nlE''L N A 2 26 L i --w ECI E #www A Hl-Ml CL-wi WFH 24 5333/3? /N VEN TOR Dec'. 24, 1940. c. ROBERTS 2,225,887

SIGNALING SYSTEM l Filed Jan. 27, 1959 v sheets-sheet 2 /Nl/EvroR B y L C. ROBERTS Dec. 24, 1940. L. ROBERTS i 2,225,887

SIGNALINQ SYSTEM l Filed Jan. 27. 1939 7 Sheets-Sheet 5 luce/wus u RECEI VING STGR/NG RELYJ' `M11/EN TOR LC. ROBERTS TronNEy L. C. ROBERTS SIGNALING SYSTEM Filed Jan. 27, 1959 '7 Sheets-Sheet 4 l l I i wma-Nro@ .C. ROBER 7`$ TTORNE Dec. 24, 1940. L c, ROBERTS 2,225,887

SIGNALING SYSTEM Filed Jan. 27, 1939 '7 Sheets-Sheet 5 I /N VEN TOR .c. ROBERTS Flc. 5

Dec. 24, 1940;

START LATCH L. C. ROBERTS SIGNALING SYSTEM Filed Jan. 27, 1959 T0 OT'ER CIRCUITS '7 Sheets-Sheet 6 /Nl/ENTOR By .C. ROBERTS Dec. 24, 1940. l D C, ROBERTS 2,225,887

' -SIGNALING sYsTEM Filed Jan. 27, 1939 '7 sheets-sheet '7 POLAR/Z50 T0 0 THE l? CIRCUI TS )Nl/ENTOR y ,C. ROBERTS Patented Dec. 24, 1940 UNITED STATES PATENT OFFICE Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application January 27, 1939, Serial No. 253,093

7 Claims.

This invention relates to signaling systems and particularly to permutation code telegraphsystems wherein messages are sent from station to station over lines extending for considerable distances through a plurality of oices.

It is an object of the invention to gain greater efliciency by using the lines as nearly up to full speed as possible. Where long lines extend between oiiices the rate of sending is limited by the frequency band-width of such lines while the loops extending from the oiiices to the stations are by reason of their greater frequency band-width capable of higher speeds. Hence it is proposed to send over the station loops by start-stop means and over the lines by straight codes containing only the signaling impulses with the start and stop impulses eliminated. Thus the code used over the lines has two less impulses than the code used over the loops and therefore higher speed may be used over the loops or poorer in duality and less expensive lines may be used. In general this object has been attained byother systems of the prior art, but the means herein set forth constitute an improvement by virtue of the employment of novel arrangements, having greater simplicity, a higher degree of dependability and lesser iirst cost.

A feature of the invention is the use of common synchronous distributors for controlling the translation of the start-stop codes in the station loops from or into the straight codes of lesser length in the lines. Where there are a plurality of lines extending from station to station through several ofces, such lines, instead of being provided with individual synchronous distributors at all oiiices for this purpose as heretofore, now are provided withrelatively inexpensive but sturdy and reliable relay means controlled by synchronous distributors common to all the lines.

Another feature of the invention is the use of a means common to the various offices for maintaining synchronism between the distributors in these offices Without the necessity for using the circuits themselves for sending synchronizing impulses. There has been established a source of standard frequency which maintains an accuracy of something like one part in a million and this has already gone into use and has tions. Since lines now extend from the source of this standard frequency to most of the large cities of the country, it is a simple matter to employ this already established means at small cost to keep the synchronous distributors in the found a number of important industrial applicavarious oiiices operating accurately together. If the network of lines under the present invention becomes large enough, a standard frequency for this use only may be used. y

A further feature of one form of the invention is the use of start-stop sending means controlled by start impulses from the receiving end. Where continuously operating synchronous distributors areemployed at the oices to control the individual line code translating and relaying means, the start-stopmeans employed for transmitting over the loops must be made to start at denite times and, hence, it has been so arranged here that start impulses are sent out by the said cornmon and continuously operating distributors to start the sending of code impulses from the other end of the loop.

The drawings comprise seven sheets, the iirst of which in Fig. l shows the invention in schematic form. The four sheets, comprising Figs. 3 tor, inclusive, when placed as shown in Fig. 2, illustrate the invention in more detail in the form of a circuit diagram. The two remaining sheets, comprising Figs. 8 and 9, when placed as shown in Fig. '7, illustrate another form of the invention again in more detail in the form of a circuit diagram.

In Fig. 1 there are three teletypewriter stations I, 2 and 3` placed in communication with three other stations, 4, 5 and 6, respectively. In this highly schematic diagram only one-way transmission is indicated but it will be quickly apparent to those skilled in the art that this is merely illustrative and in no manner restrictive for the essential elements of one-way transmission being made known, it then becomes merely the exercise of engineering skill to adaptthese principles to .two-way transmission and over the various wellknown types of transmission circuits. Here the station I sending signals has the individual im- 40 pulses distributed by an individual distributor denoted by its contact arm I to a set of recording relays 8 to I2, inclusive, by means of which through the control of impulses supplied by common distributor I3 transmits coded impulses over 45 the path I4. At the distant end of path I 4 the common distributor I5 causes the selective actuation of relays I6 to 20, inclusive, and these through the agency of common distributor 2| properly actuate the receiving apparatus at tele- 50 typewriter station 4.v The individual distributor 'I has seven small segments, a stop, a start, and five code segments so that the relays 8 to I2 are energized inaccordance with a five-unit start-,stop code. The .5.5

common distributor I3 has only ve small segments so that the impulses transmitted over the path I4 comprise only the code impulses and not the start or stop impulses.

The common distributor I5, like the distributor |3has but five small segments but the other common distributor 2| has the full seven segments for operating the regular start-stop apparatus at the receiving station.

It should be noted that the distributor I3 is common to all the incoming lines from stations such as I, 2 and 3, and that distributors I5 and 2| are common to all outgoing lines to stations such as 4, 5 and 6.

It should further be noted that all distributors in one ofce are controlled by a single source of power such as motor 22 or motor 23 and that all such sources of power are controlled from a single source of standard frequency 24. This source of standard frequency of extreme precision is wel known and has been in commercial use for some time, and having been found to be dependable, is usable here to maintain exact synchronism between these various distributors even when placed at great distances from one another.

. and distant office.

Assuming that relays 8 to Il, inclusive, for instance, have beenv energized and locked, then when distributor I3 gets to its segment 25, a circuit will be established through the common bus 26, contact and armature of relay I2, path I4, relay 20, common bus 21 and segment 28 of distributor I5. Distributors I3 and I5 are in exact synchronism so that they effectively pass over their corresponding segments at exactly the same instants and, hence, in the case assumed, relay 20 will be energized. Distributor 2|, passing over its segment 29 somewhat later, will, through the agency of relay 20, send an impulse to the station 4.

It will be understood that in actual practice the distributor I5 will be adjusted to lag behind the distributor I3 by an amount corresponding to the propagation time of the line I4. It will further be understood that several distributors corresponding to distributor I5 may be provided at an oice to care for groups of transmission lines of different propagation times. Thus, if Aline I4 is comparatively short and has a very small propagation time, the distributor I5 need vlag behind distributor I3 by only a short time.

Onfthe other hand there may be entering this "oce lines from other points which will be comparatively longer than line I4 and in that case 'another distributor like I5 could be provided lwhich would lag still more behind distributors corresponding to I3 at such other points.

Circuits illustrating the invention in more detailare shown in Figs. 3 to 6, inclusive. Figs. 3 and 4 show the arrangements at one ofce and Figs. 5 and 6 show the arrangements at another At the rst office there is a source of power illustrated as a motor 30 and at the second office a similar motor 3|. A source of standard frequency 32 which may be located at either oiiice or any other convenient location, supplies control power through line 45 yand amplifying and regulating means 33 and 34 `Vto the motors 3|] and 3| to maintain exact synchrOniSm.

Each motor is actually driven by some local source of power.

Motor 3U drives a shaft 35 to which distributor arms 36, 31 and 38, and arms for distributors `r39, 40, 4| and 42 are rigidly and permanently attached. Shaft 35. also drives a plurality of arms such as 44 through the agency of clutches, such as that indicated at 43. Such clutch arrangements are well known and will, therefore, not be described in detail.

Motor 3| drives a' shaft 46 to which distributor arms 41, 48, 49 and 50, and arms for distributors 5|, 52 and 53 are rigidly and permanently attached and a plurality of arms for distributors such as 54 are driven through clutches. All of these rigidly attached arms are shown in the same position to indicate exact synchronism.

Two teletypewriter stations are indicated at 55 and 56, and circuits are shown in detail for transmission from station 55 to station 56 and are indicated for transmission in the reverse direction. Station 55 is connected at a distance from the central ofiice, denoted in general by all the remaining diagram on Figs. 3 and 4, by means of the loop 51. Code impulses sent from station 56 operate sending relay 58 and break relay 59, while the operation of relay 66 causes the operation of the receiving apparatus at station 55, all in a manner well known. Relays 53, 59 and 60 are each shown in their marking position.

vAt the central oflice each incoming station circuit has an individual distributor such as that shown in the upper right corner of Fig. 3 and denoted by its arm 44 and clutch 43. Such distributors may be driven by the common shaft 34 or any other means or they may be in any other well-known form and it is not necessary that they be driven in exact synchronism with shaft 35. or that there be any fixed relation between the positions of the arms 44 and 36, for instance. It is only necessary that they are driven at a speed to correspond with the speed of the code contact mechanism at station 55 and at approximately the speed of shaft 35.

Code impulses are sent from station 55 in the form of seven unit codes, the first being invariably` a spacing start impulse, the second to sixth being the five permutation impulses forming the code proper, and the last being invariably va marking stop impulse.

The starting impulse being a spacing impulse, relay 58 moves to its spacing contact and thereby connects negative battery to its tongue and thence to solid ring 6|, and through the distributor` brush on arm 44 either in the position shown or 180 degrees advanced therefrom to a starting segment so that clutch release magnet 62 becomes energized. In parallel therewith the upper winding of transfer relay 63 has battery applied thereto. Now, if at the instant that this happens, arm 36 is in the position shown or in any other position where contact is made between solid ring 64 and segment 65 rather than segment 66, then the ground connection of segment 65 will cause relay 63 to become energized and this relay will lock through its lower armature, resistance 61 and its lowerI winding. It will be noted that the upper armature of relay 63 grounds conductor 68 so as to render relays 16 to 86, inclusive, subject to energization, and that the arm 38 will not reach places for the five impulses of the code and the sixth is a stop segment. As the arm 44 passes over these segments, relays 16 to 80, inclusive. will be operated or left unoperated, according to the positionof relay 58 on its spacing contact or 75 on its marking contact. If relay 58 is on its spacing contact when arm 44 reaches its first code segment, then relay 16 will become operated from the negative battery on the tongue of relay 58, ring 6|, segment 9|, upper Winding of relay 16, conductor 68, front contact and upper armature of relay 63 to ground. Relay 16 locks through its middle winding, front contact and upper armature to positive battery on common conductor 10. In this manner the permutation code sent by station 55 is written up on relays 16 to 80, inclusive-an energized relay representing a spacing impulse and a deenergized relay representing a marking impulse.

Sooner or later after the relay 16 has come underthe inuence of arm 44, the arm 38 will connect a source of current |I9 to common conductor 86 and thence through the resistance 92 to the back contact of relay 16. If this relay is deenergized, current from source ||9 will be connected to the lower armature of relay 16, thence to the transmissionconductor 93 extending to the distant office where it will cause the energization of relay 94.V Thus, relay 94 will respond to each marking impulse recorded on relays 16 to 80, inclusive, and become deenergized for each spacing impulse.

Distributor arm 31 contro-ls the deenergzation of realys 16 to 80 and as it effectively follows after arm 38, it will not affect these relays until after the record written up on them has been used. Thus, as the arm 38 moves to the position where the source of current I I9 is connected to common conductor 81, the arm 31 grounds common conductor 96 and, if relay 16 is energized, it` causes opposing current to ow in the lower winding thereof to cause the deenergization of this relay.

When the arm 44 has passed over the five code segments, it next passes over a stop segment and now ground is extended from the marking contact of relay 58 to the lower Winding of relay 63, and, due to the resistance 61, this relay is shunted down and becomes deenergized. If another code signal immediately follows, then the magnet 62 will be energized as before but, the arm 36 now having reached long segment 66, the relay 63 will not be energized and, hence, conductor 69 will be grounded and this time relays 1| to 15, inclusive, will be subject to energization. They, in turn, will be operated to write up the code signal and transmit the record over conductor 93.

If another code signal is not ready to be sent from station 55, then arm 44 comes to rest and, therefore, a relay 63 may or may not become energized when arm 44 moves again, due to the position of arms 36 to .38 at that time.

At the distant office, represented generally by Figs. 5 and 6, it will be noted that a set of relays |I to I`I0, inclusive, correspond to relays 1| to 80, inclusive. It will also be noted that, exact synchronism being maintained between arms 38 and 50, at the instant that source of current |I9 is connected to the armature of relay 16 by arm 38, that battery is connected to the upper winding of relay |06 by arm 50 through wire 91 and, hence, if relay 16 denotes a marking condition by its deenergized position, relay |06 will not be energized since relay 94 has removed ground from conductor 95 and the battery now connected to common conductor 91 is ineffective. Hence, relays |0| to |I0', inclusive, assume conditions corresponding to relays 1 I to 80, inclusive.

Just before relay |06 is to be thus aifected, distributor arm 48 reaches a position where it removes battery from conductor 98 so that any one of relays |06 .to III), inclusive, which may have been energized on a previous ro-tation of the distributor arms, will now become normal awaiting the writing up of a new code. Similarly, arm 49 causes the deenergization of any one of relays |0| to |05, inclusive, just before these relays are to be affected.

Now, whenany one of relays |06 to ||0, inclusive, becomes energized, relay 99 becomes energized and will remain in this condition until arm 48 releases such energized relays. Consequently, when distributor arm 41 nearly reaches the position in which it is shown, it will make a connection from battery, ring |00, start segment, resistance |20, front contact and armature of relay 99, conductor I|| to relay |I2. Relay |I2 moves its armature to its spacing contact and thus sends a start signal to the teletypewriter at station 56. Then, as the arm 41 moves forward, it connects battery successively to the front contacts ofv relays |06 to |I0 and, each time an energized relay is encountered, relay ||2 responds and sends a spacing contact to station 56.

If, while the code recorded on relays |06 to I I0, inclusive, is being taken off and transmitted to station 56, another code is being recorded on relays |0| to |05, inclusive, relay ||3 will be energized. When arm 41 makes about a half revolution from the position shown, a start signal will be sent to station` 56 and as arm 41 moves forward another code will be transmitted to this station.

For transmission in the other direction, station 56 will operate the relays ||4 and ||5 and the record transmitted over conductor |2| will be written up on storing relays indicated at I|0 within the broken line rectangle at the bottom of Fig. 6. 'I'his rectangle represents apparatus similar to that shown in the large broken line rectangle in Figs. 3 and 4. The record there made is transferred over the path ||1 to receiving apparatus in the broken line rectangle at the foot of Fig. 4 which represents the apparatus in the large broken line rectangle of Figs. 5 and 6, and impulses sent therefrom over conductor II8 to relay 60 which, in turn, sends the message to station 55.

The arrangements shown in Figs. 3 to 6 are representative as other variations are within the scope of the invention. For instance, all the distributors are herein arranged to take care of two codes per revolution as this seems to be a preferred arrangement but they could, with little alteration, be arranged to take care of but a single code, as is schematically indicated in Fig. 1.

The system diagrammatically illustrated in Figs. 8 and 9 shows an arrangement of this nature. Here there is a set of five recording relays |26 to |30, inclusive, for recording the code from station |22 and sending it out over the transmission conductor |23 to a corresponding set of ve recording relays |3| to |35, inclusive, at the distant end. This latter set of ve relays takes the five-unit code sent over the conductor |23 and transmits it to the station |22, translated into a seven-unit start-stop code.

It is to be noted also in this embodiment of the invention that there are no individual distributors provided. Each of the distributors |36 to |39, inclusive, is common at the sending end of the line to the various sets of recording relays, such as |26 to |30, which are themselves individual to the subscribers loops. Each of the distributors |40 to |43, inclusive, is common at the receiving end of the lines to the sets vof relays, such as `|3| to |35, inclusive, which are'individual to the subscribers loops at that oca It Will be understood, as hereinbefore explained, that the motors |44 and |45 at the various oflices are kept in exact synchronism with each other so that the shafts |46 and |41 keep thevarious distributor arms rotating synchronously..

In this embodiment of the invention, the subscriber at station |22 starts sending by operating key |48 momentarily. 'This key causes the Operation of the sending relay |50 at the oice end of the loop which operates to its spacing contact and causes the energization of slow releasing relay |5|. This relay is designed to release its armature only after a period corresponding to at least the length of a code signal. Relay |5| then being operated, a connection will be made from battery through the arm |31 to the common conductor |52 when the arm |31 gets to a point corresponding to the start segment of arm |36. This battery connection will be extended over individual conductor |53, resistance |25, the front contact and armature of slow releasing relay |5| to the upper winding of relay |55. Relay |55 operates in this circuit to its spacing contact and transmits a spacing signal to the station |22. At that point the start latch magnet |49 operates and causes the permutation code contacts at that point to begin their cycle of operations.

If, as the arm |36 moves oi its start segment to its rst code segment, the rst place in the code signal being sent by station |22 is a spacing signal and consequently relay |50 is on its spacing contact, a connection will be established from ground, the armature oi' relay |50, conductor |56, the upper winding of relay |26, common conductor |51, the first segment affected by brush |36, to battery. Relay |26 will be operated in 40 this circuit and lock from ground through its lower winding, its upper armature and iront contact to battery on conducto-r |58. Each of the following relays, |21 to |30, inclusive, will in turn be subject to energization as'the arm |36 sweeps over its segments corresponding to the second,

third, fourth and fth places of the code. In this manner, the code signal sent by the station |22 is recorded on the relays |26 to |30, inclusive.

As the brush |36 moves off the first place segment leaving relay |26 either energized or deenergized, according to whether relay |50 was on its spacing or its marking contact just previously, the brush arm |39 will come to the position shown. In this position, a source of current |60 is connected to the segment on Which it is shown as resting and, thus, the source of current |60 Will be connected to common conductor |59 and through a resistance |6| to the front contact of relay |26. Ii relay |26 has been energized by the sending of a spacing signal, then this source of current will beconnected through the lower armature of relay |26 to transmission conductor |23 Which at the other end affects the receiving apparatus to operate relay |62. Thus, relay |62 will operate each time a spacing signal is sent and will remain deenergized each time a marking signal is sent.A This, in turn, means that conductor |63 Will present to the relays |3| to |35, inclusive, a ground connection for each marking signal and an open connection for each spacing signal.l

The brush arm |38 eiectively trails behind the brush arm |39 so that if the brush arm |39 is on its second segment, brush arm |38 is on its first segment, that is, after the record Written on the relays |26 to |30, inclusive, has been transferred to the transmission conductor |23, the brush arm |38 wipes out the record by connecting ground, for instance, to conductor |64 through the middle winding of relay |26 so that a magnetization equal and opposite to that produced by the lower winding is now set up and relay |26 becomes deenergized.

As the brush arms |36 to |36 rotate, the arm |36 will come to a stop segment and thereafter to a start segment. At this time, brush arm |31 will again send a start signal to the subscribers station |22 and another code Will be Written up on relays |26 to |30, inclusive. It Will be remembered that this depends on the energization of slow releasing relay |5| and that to maintain this relay energized there must be at least one spacing segment per code. If, therefore, the station |22 ceases to send code signals, relay |50 will remain on its marking Contact and relay |5| Will become deenergized.

At the receiving end, relays |3| to |35 are sequentially rendered operable by the movement of brush arm |43. If this arm is in a position corresponding to the rst code signal position of brush arm |39 at the distant office, a spacing signal having the control of energization of relay |26 will now cause the transmission of current from source |60 over the transmission conductor |23 and thus the energization of relay |62 Whereby ground is removed from conductor |63 so that atthis time relay |3| being under the influence of brush arm |43 will not be energized. If, on the other hand, a marking signal had resulted in the non-operation of relay |26, then relay |62 would not have been operated and ground would be connected to conductor |63, thence through the lower winding oi relay 3 I, the common conductor |65, brush arm |43, to battery, so that relay |3| would become energized on the marking signal. Similarly, relays |32 to |35 will be energized or nonenergized according to the transmission of marking or spacing impulses as the brush arm |39 successively passes over the segments leading to the relays |21 to |30, inclusive.

If relay |3|, |32, or |33 become energized, these relays Will lock from ground over their upper windings, upper armatures and front contacts, to common conductor |61, through brush arm |42 to battery, which connection is effective While brush arm |43 is passing over contacts associated with relays |3|, |32, |33. Relays |34 and |35 lock to common conductor |68 associated with brush arm |4| so that these relays will be maintained energized until the brush arm |40 has reached the segment on which it is shown and passed thereover. A start signal for station |24 Will be trans mitted by the open circuit condition when brush |40 passes over the segment on which it is shown, relay |1| not being operated. Relay |12 controls the sending of spacing and marking impulses to the station |24. The connection just described will send a spacing pulse to station |24. Ihereafter, as arm |44 progresses it will successively connect battery to the front contacts and lower armatures of relays |3| to |35, inclusive, and, thus, send marking impulses when these relays are energized and spacing impulses when they are non-energized.

Transmission in the other direction is indicated here only by the conductors |13 and |14 corresponding to conductors |53 and |56 and by conductor |15 at the other end corresponding to conductor |63.

What is claimed is:

1. A signaling system comprising oices distant from each other, a plurality of signaling stations, lines, each extending from one of said stations through said oilces to another of said stations, means at said offices for relaying signals over the lines passing therethrough and for translating such signals from one code to another, means at each oice common to said lines for controlling said relaying and translating means and means common to said oflices for controlling said first common means.

2. A signaling system comprising offices distant from each other, a plurality of signaling stations, lines, each extending from one of said stations through said oices to another of said stations, a relaying and translating means in each of said lines at each of said ofces for relaying signals passing over said lines and for translating such signals from one code to another, means at each office common to said lines for controlling said relaying and translating means and means common to said oii'ices for controlling said rst common means.

3. A signaling system comprising ofces distant from each other, a plurality of signaling stations, lines each extending from one of said stations through said offices to another of said stations, means individual to each of said lines at each of said ofces for receiving and recording signals in one code, and transmitting corresponding signals in another code, means at each office common to said lines for controlling said individual means and means common to said offices forv controlling said rst common means.

4. A signaling system comprising oiiices distant from each other, a plurality of signaling stations, lines each extending from one of said stations -through said offices to another of said stations, means for signaling from station to station by codes of a uniform and given number of signal elements per character in the portions of said lines between said stations and said ofces and by corresponding codes of a uniform and lesser given number of signal elements in the portions of said lines between said oiiices, code changing means individual to each line at each of said oiices, means at each of said oices common to the lines thereat for controlling said code changing means and means common to said offices for causing said code changing controlling means to operate in synchronism.

5. A signaling system comprising oices distant from each other, a plurality of signaling stations, lines each extending from oneof said stations through said oices to another of said stations, means for signaling from station to station by permutation code, means for using oontrolling impulses in addition to thecode impulses for each character between said stations and said oi'lices and only the permutation code impulses between said oiiices, relay storing means individual to each line at each of said oi'ces for effecting the said translation of code with controlling impulses to and from code without controlling impulses iand means at each of said offices common to the lines thereat for controlling said relay means.

6. A signaling system, comprising oiiices distant from each other, a plurality of signaling stations, lines each extending from one of said stations through said oflices to ano-ther of said stations, start-stop means for signaling between said stations and said oiices, and continuously operatingV synchronous means for signaling between said ofces, said last means being common to said lines. t

7. A signaling system comprising oidces distant from each other, a plurality of signaling stations, lines each extending from one of said stations through said ofces to another one of said stations, means for signaling from one vsta-- tion to another comprising start-stop permutationcode sending means at one station, individual start-stop receiving means at a rst office, an individual set of storing relays thereat controlled by said start-stop means, permutation code sending means common to said lines at said oiiice cooperating with said storing relays, another set of storing relays lat another oice individual to said line, permutation code sending means at said other oce common to said lines cooperating with said individual set of storing relays and start-stop receiving means at said other station controlled thereby.

LELAND C. ROBERTS. 

